1. Field of the Invention
This invention relates to workstation viewing images of digital documents stored on a network server and in particular to viewing large digital document images using a client-server architecture.
2. Description of the Prior Art
Current methods for viewing digital document images for workstations in a networked environment use proprietary workstation application software to access a network image file server. To view an image, the application software transfers a copy of the whole image file from the image file server to the networked client workstation This method has a number limitations including: inefficient use of the network; high software purchase cost per workstation; high software administrative cost per workstation; high computational demands on the workstation; proprietary software available only for limited workstation types. Some other network image viewers may provide viewing using more optimized image transmission protocols but only with proprietary protocols and proprietary workstation software.
It is an object of the invention to provide a method of obtaining graphical images from a network server for viewing at a computer workstation which does not require proprietary workstation software.
It is another object to provide such a method which makes efficient use of the network and results in greater speed of image display in response to requests from the workstations.
It is another object to provide such a method which makes use of caching mechanisms resulting in a balanced load on the network file server and a faster response time to a single client when many clients are accessing the server simultaneously.
It is another object to minimize the computing resources required by a client workstation.
A further object is to provide apparatus for storing graphical images, requesting portions of the stored graphical images from storage, and quickly and efficiently displaying the images on a workstation.
A still further object is to provide a computer program which facilitates requesting portions of graphical images stored on a network server and displaying those portions on a workstation.